Manufacture of footwear and parts therefor



Oct. 17, 1944. E. L. CRANDELL MANUFACTURE OF FOOTWEAR AND PARTS THEREFOR Filed April 10, 1941 2 Sheets-Sheet l Oct. 17, 1944. E. L. CRANDELL MANUFACTURE OF FOOT Filed April 1 0, 1941 WEAR AND PARTS THEREFOR 2 Sheets-Sheet 2 to the following features Patented Oct. 17, 1944 2,360,763 MANUFACTURE OF FOOTWEAR AND PARTS THEREFOR Ervin L. Crandell, Wellesley, Mass, assignor to Compo Shoe M Mass., a corpora Application April 10, 1941, s

2 Claims.

n relates to the manufacture of footwear, and more particularly to a form of manufacture wherein shoes, or certain parts thereof, are heated by the action of a high frequency electrical field to activate heat responsive materials in the shoe construction, such as thermoplastic bonding adhesives.

General objects of the invention are to provide shoe constructions and shoemaking methods wherein an electrically conductive material such as metallic foil or mesh is incorporated as a permanent component such a manner as convenien as an electrode employed in s field.

More particularly, to provide shoe parts a incorporated in a shoe at or near portions thereof which are to be thermally treated by the heating action of an energized electric field, wherein such parts include a ply of electrically conductive material capable of being arranged in that portion of the finished shoe which is to be thermally treated.

Further object o a cement sole attac This inventio tly to enable its use etting up a heating objects of the invention are f the invention'are to provide hing construction and method wherein a thermoplastic adhesive is placed between the outsole and the lasted upper and is subjected to the heating effect of an electrostatic field set up between electrodes, one or more of which is located beneath the outsole, and another of which forms a component part of the shoe construction, such as an insole or an upper.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several'steps and the relation of one or more of such steps with respect to each of the others, and the articles possessing the features, properties, and the relation of elements, which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention reference should be had detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 is a perspective view of a partly lasted shoe showing an insole construction embodying of the invention;

Fig. 2 is a longitudin lasted shoe constructed showing the outsole a matically indicating the on trode arrangement;

in accordance with Fig. 1 ttached and diagramtsole attaching elechinery Corporation, tion of Delaware Boston,

erial No. 387,823

f the.shoe construction in' dapted to be permanently perspective view showing another e embodying features of the inven- Fig. 3 is a form of insol tion;

Fig. 4 is a perspective view showing an outsole embodying features of the invention;

Fig. 5 is a transverse vertical sectional view across the forepart of a shoe having a special upper embodying features of the invention and showing a fragmentary portion of an electrode equipped sole pressing pad associated therewith; and

Fig. 6 is a par shown in Fig. 5,

tial plan view of the shoe structure the outsole being removed.

The present invention generally contemplates using a high frequency source of inductive heating such as that described in the patent to E. C. Pitman, No. 2,087,480, issued July 20, 1937, and a thermoplastic or thermosetting adhesive or plastic which is heated on or between plies of other materials by the action of the high frequency energized field.

The Pitman patent discloses that when attaching outsoles to shoes, this field may be set up between an electrode on the last bottom and one on the sole pressing pad of a sole affixing press, which embraces the shoe bottom including the thermoplastic sole bonding area between them. In factories where the lasts have no metal bottoms, or where, for some reason, such bottoms cannot readily be employed for electrode purposes, it is necessary in such an arrangement to provide a special electrode on the last bottom, of the kind shown, for example, in the Smith Patent No. 2,240,867.

a1 vertical section of the The present invention contemplates avoiding the trouble and expense of refitting lasts in ,this manner by incorporating an inexpensive conductive electrode ply in or on at least one portion of the shoe part itself at a point adjacent the thermoplastic together with means for connecting such insole electrode in a high frequency circuit.

Referring particularly to the drawings, and first to Figs. 1 and 2, there is shown a shoe lasted on a last l0 whichv may be of conventional construction except that the usual metal jack pin thimble ll may have an electrically conductive pin l2 extending from the bottom thereof downwardly to the bottom of the last where its lower end is exposed for contact with the adjacent portion of an insole there located. Also, the usual tack clenching metal plate at the heel seat of such last designated I3 is preferably cut away as indicated at M to avoid electrical contact with the conductor l2. The shank and forepart portions of the last bottom need have no metal plating nor like electrode construction in view of the incorporation of such parts in other portions of the lasted shoe in the manner about to be deillustrated the upper is cement overlasted against the underface of the insole, although stitching or even metal staple lasting may be desired.

The insole I7 is of laminated construction comprising an upper or foot-side ply I8 and a lower or sole-side ply I9 having between them a ceemployed if conductive material such as fine copper mesh, Where a foil rather than a mesh is used, such foil may preferably be perforated or cut away from those areas in which an electric heating field is not particularly desired in-order to afford a direct cemented bond between the insole plies I8 and relatively non-conductive material such as leather or fibre composition. The foot side ply I8 has a slot 2I near the heel breast line through which a rearwardly extending tongue or connector 22 is led for exposure on the inner face of the insole next to the last bottom and beneath the conductor I2.

In making a shoe such insole is located on the last bottom with the electrode tongue 22 in contact with the conductor I2 and the upper is lasted thereto. The lasting allowances of the upper and of an outsole 23 are then roughed and coated with a thermoplastic adhesive, preferably one of the thermoplastic types described in the mentioned Pitman Patent 2,087,480, such as vinyl resin in atoluol solution. The adhesive may be allowed to drythrough evaporation of the solvent ready for subsequent activation by a high frequency electrostatic field. This field is applied by placing the shoe and outsole with, if needed, a suitable filler 24 therebetween and with their cemented faces in contact, in a suitable shoe press, not shown, having a flexible electrode associated with its sole engaging pad and underlying at feast the shank and forepart areas of the shoe sole. Such an electrode 25 is diagrammatically represented beneath the outsolein Fig. 2, being shown opposed to the metallic foil or mesh electrode 20 forming a component part of the insole. The shoe press pad electrode is shown connected to the power side of any suitable type of high frequency generator, w 1c the last jack pin thimble is connected with. the ground side of such a circuit, thus connecting'the insole electrode I8 through. the conductor I2 with the circuit. If desired, the insole electrode may be connected with the power side of the high frequency generator circuit and the shoe press pad-electrode grounded, or. the opposed electrodes may be'connccted with opposite sides of a push-pull oscillator circuit, all as is well understood in the art of generating high frequency current. the shoe is held in the press under suitable sole affixing pressure, an electrostatic field is set up between the insole and pad electrodes, preferably at the frequency of 20 to 25 suitable period of time and at a suitable power value, although these features, including the frequency employed, will depend on the individual shoe construction, type of adhesive, etc., and are unnecessary to an understanding oi' the use of the particular electrode construction herein claimed.

aaeones conductive material side thereof and another piece of conductive to form a continuous The heel tab serves to form an electrical connection with the last thimble extension I2 (Figs. 1 and 2) and can be removed from the finished shoe if desired.

Thus the form of adapted to serve same and can be speedily and cheaply manufactured.

In Fig. 4 another form of my invention is shown which comprises a laminated outsole unit adapted for adhesive attachment to a lasted upper.

and askiving or split can be utilized for the attaching face or foot Referring to Fig. 4, the outsole unit consists of a Wearing ply 40 and an upper ply 4| which can, be skived, roughed, and cemented in the usual manner for attachment to a shoe upper: Cemented between these leather plies is a sheet of metallic foil or mesh 42 which is provided with a pro ecting lip 43 which serves as a convenient connection to one side of a suitable high frequency generator. In attaching this outsole unit to a shoe bottom,

as hereinafter described.

An arrangement whereby a shoe upper is provided with an electrode which forms a part of the shoe structure is shown in Fig. 5. This structure comprises a shoe upper 45 and its lining 46. Around the lasting allowance'is sandwiched a strip of metallic foil or the like 41 which is secured by the stitches 48 or by any suitable adhesive. The entire upper is shown lasted over a conventional insole 49, its lasting allowance having been roughed, cemented, and the filler piece 50 and outsole 52 in place ready for the sole affixing operation.

The electrode sandwiched between the upper and lining is provided with an extension 5| as shown in Fig. 6 to serve as a connection to the high frequency electrical source. This extension 5| can readily be formed by allowing the foil to continue beyond the heel breast line and then allowing it to protrude out between the lining and upper and simplybending same over, subsluntially as shown.

1n attaching a sole 52 to the shoe structure described, it is only necessary to connect one of the high frequency source to the electrode extension 5i, on a suitable shoe press pad electrode diagram matically represented in Fig. 5.

Since certain changes in carrying out the above process. and certain modifications in the articles which embody the invention may be made without departing from its scope, it is intended that all matter. contained in the above description or shown in the accompanying drawings shall be inter reted as illustrative and not in a limiting sense;

side i and then seat the shoe and outsole Having described my invention, what I claim as new and desire to secure by Letters Patent, is: 1. A laminated insole having upper and lower plies and an interior ply of metallic material, said upper ply of said insole having a slot formed 

